1. Technical Field
The present disclosure of invention relates to a display substrate and a method of manufacturing the display substrate. More particularly, the present disclosure of invention relates to a low temperature poly-silicon (LTPS) display substrate and a method of manufacturing the display substrate.
2. Discussion of Related Art
A display panel of a Liquid Crystal Display (LCD) or alike display device typically includes a transistor array substrate and a facing substrate facing the transistor array substrate with spacing there between often filled with a fluid such as a liquid crystal. The transistor array substrate typically includes a plurality of transistors used for example, for selectively addressing pixels and selectively altering their optical states. The transistor array substrate may also include circuit transistors monolithically integrated into the non-display or peripheral areas of the transistor array substrate.
Pixel addressing transistors such as those described above (often also referred to as the switching elements of the display device) may be classified into, for example, an amorphous-silicon (a-Si) type of TFT (thin film transistor), a polycrystalline silicon (poly-Si) type of TFT, etc., in accordance with characteristics of an active semiconductive pattern included in the transistor structure.
The poly-Si type of TFT typically has a higher electron mobility as compared to the a-Si type of TFT, so that it is possible to realize a desirable higher speed of driving for the corresponding display device. In contrast, the poly-Si type of TFT typically has a more complex manufacturing process than does the a-Si type of TFT so that manufacturing costs of the former tends to be higher than that of the a-Si type of TFT.
It may require high temperatures to form a poly-Si type active layer. Thus, the kinds of materials used for forming electrodes (e.g., gate electrode) of the poly-Si TFT may be limited.
On the other hand, nowadays, display devices are tending to become physically larger, higher resolutions are required, and thinner and longer signal lines are needed for applying gate driving signals or data driving signals to the pixels of the display. As a result RC delay becomes a problem.
In the past it was common to form the TFT gate electrode as an integral extension of the adjacent gate line. However, when the material used as the gate electrode of the poly-Si TFT is employed to also form the gate line, the resistance of the gate line may become excessively large and generate an unacceptable resistance-capacitance (RC) based delay for gate line signals.
It is to be understood that this background of the related technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein.